Exact Outage Probability of Cognitive Underlay DF Relay Networks with Best Relay Selection

In this letter, we address the performance analysis of underlay selective decode-and-forward (DF) relay networks in Rayleigh fading channels with non-necessarily identical fading parameters. In particular, a novel result on the outage probability of the considered system is presented. Monte Carlo simulations are performed to verify the correctness of our exact closed-form expression. Our proposed analysis can be adopted for various underlay spectrum sharing applications of cognitive DF relay networks. key words: decode-and-forward, relay networks, underlay approach, interference constraints, outage probability, cognitive radio